1. Field of the Invention
The present invention relates to a sheet handling apparatus (to be referred to as a sorter hereinafter) which performs sorting and storage of paper sheets (to be referred to as sheets hereinafter) such as copying sheets or recording paper sheets which are conveyed after images are formed thereon by an image formation apparatus or recording equipment, such as a copying machine or a printing press.
2. Description of the Prior Art
A sorter generally has 10 to 20 or more sheet storages (tray or bin group). Sheets are conveyed at predetermined intervals from an apparatus, such as a copying machine, and are sequentially fed into and stored in predetermined trays by a convey means such as a belt, a plurality of rollers or a combination thereof.
When such a sorter is used in combination with a copying machine, the sorter has a sort mode, a non sort mode, and a collate mode. In the sort mode, sheets sequentially exhausted from the copying machine are stored and stored in predetermined trays. In the non sort mode, all the sheets are stored in a predetermined or special tray. In the collate mode, sheets of the same type are stored in the same tray.
Even if the sorter operates in many such modes, the number of types of signals exchanged between the copying machine and the sorter is preferably small from the viewpoints of cost and reliability. The effects obtainable with such a reduction in the number of types of signals exchanged between the copying machine and the sorter are significant, especially in a copying machine and sorter of simple configuration.
When jamming or short supply of toner occurs in a copying machine, if a sorter connected thereto is supplied with power from the copying machine, the power of the sorter is turned off during the process of jammed sheet removal or toner replenishment. If the sorter is in the sort mode before the power is turned off, the sequence mode immediately before such a process must be restored on power resumption.
A conventional sorter is known wherein the group of trays at the exhaust port of a copying machine or the like is sequentially moved so as to perform sorting and storage of sheets.
A sorter of this type sometimes has a sheet detecting means arranged immediately before the convey means of the sorter so as to monitor sheet convey failure. The sheet detecting means comprises, for example, a lightweight element such as a combination of a reed SW (switch)and an actuator. When the sheet is conveyed, the actuator is caught by the conveyed sheet and is detected by the reed SW.
This sorter has a configuration wherein after the conveyed sheets are completely stored in trays, the tray group is moved for the next operation. For this reason, if the sorter is subject to some vibration, especially, if the operator moves the sorter to the exhaust port of the copying machine too roughly, the sheet detecting means is actuated due to its light weight. The detecting means thus produces an erroneous output indicating that the sheet has been conveyed, and the tray group is moved, presenting a danger to the operator.
In such a system as described above, electric interfacing between the sorter and the copying machine is controlled by the conversation method.
According to one known configuration, when the copy start key of the copying machine is depressed, a sorter operation start signal is supplied to the sorter. Then, the sorter moves the trays to predetermined positions. When the trays ar completely moved to the predetermined positions, the sorter supplies a sorter standby signal to the copying machine. The copying machine then starts the copying operation and the produced copy sheet is exhausted.
In the system having the configuration described above, the sorter is set in the standby mode in response to the sorter operation start signal and is kept in this mode until the copy sheet is exhausted from the copying machine. However, if the copying machine does not produce any copy sheet due to either depression of the stop key or jamming, the standby mode of the sorter must be released. This requires the use of a third signal in addition to the sorter operation start signal and the sorter standby signal, thus increasing the number of signals to be handled.
In a sorter of the type described above, the trays are generally arranged at equal intervals, and the tray interval is narrowed when the corresponding tray is to receive the conveyed sheet. After the conveyed sheet has been received in the corresponding tray, the narrow interval must be reset to the regular interval. When the sheet convey at the inlet opening of the tray is interfered with, the sheet is jammed between adjacent trays. Removal of the jammed sheet from the narrow interval between the trays is then very difficult.